1. Technical Field of the Invention
The present invention relates to an optical pointing device for moving a cursor on the display screen of an information processing apparatus such as a personal computer or a workstation computer, an optical pointing device control method and a computer program product or recording medium recording the same. The present invention particularly relates to an optical pointing device realizing a thin, lightweight device and having improved reliability, a control method therefor and a recording medium recording the same.
2. Description of the Prior Art
It is conventionally well known that an optical track ball provided integrally with a notebook personal computer main body is an excellent pointing device. The optical track ball is a device mechanically transmitting a rotating ball following the rotation movement of the ball in an arbitrary direction and rotating an encoder ring. The optical track ball then detects an optical variation including the on and off of light following the rotation as an optical pulse, converts coordinate information according to a movement direction and a movement quantity into an electric signal and moves a cursor on a computer screen.
A conventional optical track ball will be described hereinafter with reference to the drawings.
FIG. 13 is an exploded perspective view showing the schematic constitution of the conventional optical track ball. FIG. 14 is a view seen from an arrow A in FIG. 13. FIG. 15 is a detailed view of an encoder ring shown in FIG. 13.
Referring to FIGS. 13 to 15, the optical track ball 10 consists of an upper housing cover 13 integrally comprising a right click button cover 11 and a left click button cover 12, a lower housing cover 26 and a control circuit board 17 provided within the lower housing cover 26. On the control circuit board 17, a Y axis shaft encoder 28 consisting of a roller 20, an encoder ring 22 and a shaft 21, a support 25 supporting the Y axis shaft encoder 28, an X axis shaft encoder 14 consisting of a roller 35, an encoder ring 31 and a shaft 32, a support 34 supporting the X axis shaft encoder 14, a light emitting device 24 and a photo-detector 23 for an X axis direction between which the encoder ring 22 is provided, a light emitting device 33 and a photo-detector 30 for a Y axis direction between which the encoder ring 31 is provided, a right click button 15 and a left click button 16 are mounted.
A space 18 having an upper portion protruding to rotate and move a ball 19 is provided in the upper housing cover 13. The lower housing cover 26 and the upper housing cover 13 are assembled into a main body computer (not shown) by screws 27.
Next, the operation of the optical track ball 10 constituted as stated above will be described with reference to the drawings.
Referring to FIGS. 14 and 15, the X axis direction roller 35 and the Y axis direction roller 20, the phases of which rollers are different from each other by 90xc2x0, contact with the ball 19. In the movement of the ball in the X axis direction, the roller 35 in contact with the ball 19 is driven to follow the rotation movement of the ball 19, so as to rotate the shaft 32 connected to the roller 35 and supported by the support 34.
The encoder ring 31 arranged between the light emitting device 33 and the photo-detector 30 and having slits 52 is connected to the shaft 32. The encoder ring 31 rotates, thereby detecting changes in the on and off of light arriving at the photo-detector 30 from the light emitting device 33 as an optical pulse string, converts coordinate information according to a movement direction and a movement quantity into an electric signal, and moves the cursor on the computer screen.
In the movement of the ball 19 in the Y axis direction, as in the case of the above-stated X axis direction, the roller 20 in contact with the ball 19 is driven by the rotation of the ball 19 followed by the movement thereof, so as to rotate the shaft 21 connected to the roller 20 and supported by the support 25.
The encoder ring 22 provided between the light emitting device 24 and the photo-detector 23 and having slits 52 uniformly arranged thereon is connected to the shaft 21. The encoder ring 22 rotates, thereby detecting changes in the on and off of light arriving at the photo-detector 23 from the light emitting device 24 as an optical pulse string, converts coordinate information according to a movement direction and a movement quantity into an electric signal, and moves the cursor on the computer screen.
Referring to FIG. 15, each of the encoder rings 22 and 31 is circular, a plurality of slits 52 are uniformly and radially arranged about the shaft 21 or 32 and radiated light from the light emitting device 24 or 33 arrives at the photo-detector 23 or 30 through these slits 52. The distance, area and shape of the slits 52 are closely related to the resolution of the cursor, i.e., the movement distance of the cursor per unit length when the cursor moves.
As stated above, the rotation movement of the ball 19 is required to accurately synchronize with the movement of the cursor. Due to this, the conventional optical track ball 10 requires a structural component preventing a slip loss that only the ball 19 rotates and the rollers 20 and 35 cannot be driven, by constantly bringing the ball 19 into contact with the rollers 20 and 35 with equal forces. A press roller 45 shown in FIG. 14 is a spring structural component consisting of a pressure spring 44 and a rotational roller 43. The press roller 45 is suited to properly maintain the positional relationship between the ball 19 and the rollers 20, 35. However, while the ball 19 freely moves in a ball gauge (not shown) longitudinally, laterally and vertically, the press roller 45 is fixed and cannot completely follow up the movement of the ball 19. For that reason, the press roller 45 has disadvantages in that it cannot completely prevent the slip loss of the ball 19 and deteriorates reliability.
Further, the conventional optical track ball 10 requires many complicated structural components in a mechanically movable section, disadvantageously increasing component cost, assembly cost and component and assembly management cost.
Moreover, the ball 19 serving as the mechanically movable section of the structural components, the encoder rings 22 and 31 rotating in response to the movement of the ball 19, the supports 25 and 34 and the press roller 45 consisting of the pressure spring 44 and the rotational roller 43 are tallest components among the structural components and unsuited for providing the device of shorter stature. Thus, the conventional optical ball is disadvantageously unsuited to be used y integrally with an apparatus, typically a notebook computer, having a limited stature and a limited space.
As stated above, a mechanical slip loss inevitably occurs between the ball serving as the mechanically movable section among the structural components and each shaft encoder rotating in response to the movement of the ball when the rotation of the ball is transmitted from the ball to the roller of each shaft encoder. Due to this, the conventional optical track ball disadvantageously deteriorates reliability.
In addition, the conventional optical track ball requires many complicated structural components, disadvantageously increasing component cost, assembly cost and component and assembly management cost.
Moreover, the ball serving as the mechanically movable section among the structural components, the shaft encoder, the supports and the press roller consisting of the pressure spring and the rotating roller are tallest components among the structural components and unsuited for providing the device of shorter stature. Thus, the conventional optical ball is disadvantageously unsuited to be used integrally with an apparatus, typically a notebook computer, having a limited stature and a limited space.
It is an object of the present invention to provide an optical pointing device capable of solving the above-stated problems by changing the movement of a mechanically movable section of structural components from three-dimensional movement to two-dimensional movement, that is, making the mechanically movable section movable in a plane.
The optical pointing device of the present invention is characterized by comprising: a pointing board having stripe-like line patterns provided in an X axis direction and a Y axis direction, respectively, the patterns orthogonal to each other, and having a protruding portion; an upper housing cover covering an upper surface of the pointed board, and having an opening portion provided around the protruding portion of the pointing board, a left click button cover, and a right click button cover; a click button control circuit board mounting thereon a left click button and a right click button arranged right under the left click button cover and the right click button cover, respectively, and a first thin flexible cable connector, the click button control circuit board fixedly attached to a lower surface of the upper housing; and a control circuit board having a support base supporting the pointing board, a light emitting device irradiating light to the light patterns, a photo-detector detecting an optical change due to reflection or cutoff of irradiated light from the line patterns, and a control circuit controlling a signal from the photo-detector and signals from the left click button and the right click button.
Further, the optical pointing device control method of the present invention is characterized by comprising: moving a pointing board having stripe-like line patterns provided in an X axis direction and a Y axis direction, respectively, the line patterns orthogonal to each other, and having a protruding portion, by operation of the protruding portion, thereby detecting, by means of a photo-detector, as an optical pulse string, an optical change due to reflection or cutoff of irradiated light occurring when the irradiated light from a light emitting device provided on a control circuit crosses the line patterns, and converting coordinate information according to a movement direction and a movement quantity of the pointing board into an electric signal.
Further, the computer program product, or recording medium of the present invention is characterized by being a recording medium recording an optical pointing device control program.
As stated so far, the optical pointing device of the present invention has advantages in that the pointing board moving two-dimensionally in the plane is provided as the mechanically movable section, whereby the structure of the mechanically movable section can be simplified, the device of short stature can be provided and the device can be used integrally with an apparatus having a limited stature and a limited space.
Further, since the number of the components of the movable section can be greatly reduced, it is possible to reduce component cost, assembly cost and component and assembly management cost and it is also possible to improve the yield of a production line and reliability, thereby making it possible to deal with the realization of assembly automation.
Moreover, by providing the protruding portion for movement operation and forward direction lines which become marks for the movement direction are provided on the pointing board, the cursor on the display screen is moved in the same directed direction as that of the pointing board. Hence, the optical pointing device of the present invention is advantageously excellent in pointing direction.